This invention relates generally to an electrophotographic printing machine, and more particularly concerns a development apparatus employed therein.
In the process of electrophotographic printing a photoconductive member is charged to a substantially uniform level. Thereafter, a light image of an original document being reproduced is projected onto the charged portion of the photoconductive member to record an electrostatic latent image thereon. A developer mix comprising carrier granules and toner particles is brought into contact with the electrostatic latent image. The toner particles adhere triboelectrically to the carrier granules. The electrostatic latent image attracts the toner particles from the carrier granules forming a toner powder image on the photoconductive member. The toner powder image is transferred from the photoconductive member to a sheet of support material. Thereafter, the toner powder image is permanently affixed to the sheet of support material forming a copy of the original document being reproduced.
Generally, an electrophotographic printing machine utilizes a developer mix of carrier granules and toner particles. However, toner particles are continually being depleted from the developer mix as they are attracted from the carrier granules to the latent image recorded on the photoconductive member. For this reason, an electrophotographic printing machine generally utilizes a toner replenishing device for furnishing additional toner particles to the developer mix as it is consumed therein. A typical toner particle replenishing device may employ an open-ended box for storing toner particles therein. A plate having a grid structure moves across the open end of the box to dispense toner particles therefrom. However, a toner particles dispenser of this type may have numerous difficulties associated therewith. For example, frequently large quantities of toner particles are dropped into the developer mixture due to the pressure of the toner particles in the housing. In addition, the concentration of toner particles is not uniformly distributed within the developer mix. This may result in copy quality degradation.
Accordingly, it is the primary object of the present invention to replenish toner particles substantially uniformly to a developer mix.